This invention relates to washing drums or barrels of the type which typically contain hazardous or dangerous materials, after the materials have been dispensed from the drums. More particularly, the present invention relates to a new and improved method and apparatus for washing the interior of a hollow drum in an easier and safer manner while reducing the amount of water used, by spraying the interior of the drum with a cleaning solution.
Drums or barrels are typically used by chemical manufacturers to transport various hazardous, corrosive, or reactive chemicals used in industrial processes. For example hazardous chemicals such as sulfuric acid, hydrochloric acid, hydrofluoric acid and corrosive polishing compounds are shipped in drums to semiconductor fabricators. The drum is typically made of a polyurethane or other plastic material so that the drum material does not react with the chemical retained in the drum.
When the chemical contents are removed from the drum through the bung holes formed in an end cover of the drum, a residue of the chemical remains on the interior surfaces of the drum. It is a typical requirement under department of transportation regulations and health and safety regulations that the drum must be cleaned of the interior residue prior to transportation of the drum on public highways and in public places. A typical requirement is for a triple washing of the drum. The triple washing standard requires the drum to be rinsed on three separate occasions. The three separate washings are regarded as sufficient to clean the drum enough for public transportation.
The typical method of performing the triple washing procedure is to fill the drum completely with water through one of the bung holes. The drum is then turned over to drain the water from the inside of the drum. This process is repeated three times using clean water during each rinse. This process of triple washing the empty drum consumes a relatively large quantity of water. A typical drum holds fifty-five gallon, thus requiring 165 gallons of water to wash using the conventional triple washing method. In addition, it is difficult for a person to turn the drum over once it has been filled with water because of the weight of the water-filled drum. The difficulty of turning over the relatively heavy water-filled drum also raises issues the possibility of human contact with the chemical residue, because of the difficulty in lifting and manipulating the water-filled drum.
These and other considerations pertinent to the previous processes of washing drums which contain chemical residue has given rise to the present invention.
One aspect of the present invention relates to rinsing the inside of a drum to a level of cleanliness achieved with a triple washing standard by using only a relatively small amount of water compared to the amount of water typically required to fill each drum three times. Another aspect of the invention relates to rinsing the inside of a drum in a manner which does not require the drum to be inverted or otherwise manipulated by human contact while the drum is washed. Yet another aspect of the invention relates to avoiding the necessity to manipulate relatively heavy water-filled drums during washing.
In accordance with these and other aspects, the invention relates to a drum washer apparatus. The drum washer includes a base support structure, a barrel support structure connected to the base structure for supporting the drum in a position in which a top cover of the drum is below a bottom cover of the drum, and a fluid delivery system for delivering cleaning fluid into the interior of the drum. The fluid delivery system includes one or more spray heads which are inserted into one or more bung holes in an end cover of the drum by which to spray the cleaning fluid onto the inside surfaces of the drum. The empty drum is turned over and placed onto the drum washer by inserting spray heads of the drum washer into the interior of the drum through holes in the top cover of the drum. The cleaning fluid spray completely contacts the interior surfaces of the drum, and the spray is maintained for a predetermined amount of time sufficient to thoroughly wash the interior surfaces of the drum. The cleaning fluid which accumulates within the interior of the drum during spraying is allowed to drain from one or more of the bung holes. The cleaning process is preformed three times, each for the predetermined time, and results in a drum that has been cleaned and rinsed sufficiently to satisfy the triple washing standard.
Preferred aspects of the drum washer include wheels mounted to the base structure for providing mobility to the drum washer. The wheels allow the drum washer apparatus and the drum positioned on it to be moved conveniently over a neutralization pit which collects the spent rinse water or washing fluid. The spent washing fluid is typically collected in a holding or neutralization tank where the Ph level (of the water) is adjusted before the water is returned to a city water waste system. The cleaning fluid delivery system may include a spigot valve for controlling the predetermined delivery time of the flow of the water or cleaning fluid to the spray heads. The convenience of the spigot valve facilitates a convenient execution of the three separate washings.
In accordance with these and other aspects, the invention also includes a method for rinsing the inside surfaces of the drum. The drum is placed in a position in which the top cover is below the bottom cover. Water or other washing fluid is delivered through one or more holes in the top cover of the drum and onto the interior of the drum. Inside surfaces of the drum are rinsed and the cleaning fluid is then allowed to drain out one or more of the holes in the top cover of the inverted drum. To preferably the cleaning fluid is sprayed onto the inside surfaces of the drum.
A more complete appreciation of the present invention and its improvements can be obtained by reference to the accompanying drawings, which are briefly summarized below, by reference to the following detailed description of a presently preferred embodiment of the invention, and by reference to the appended claims.